The assembling of a sewing machine is an extensive operation, since many of its parts have to be assembled with great precision, and the openings in the body are often very limited. One method to achieve a greater accessibility is to make the openings larger, but this means that the body obtained a nonuniform and irregular appearance and less stability. Many parts of the machines can be combined to larger units, which are then placed in prepared seats in the body. This method of assembly of the machine requires appreciably less work within the body itself and is also labor-saving as a whole. This method can be applied in particular to sewing machine bodies with fully open front or rear. The body thus open with its prepared or precast seats for journal bearings and points of attachment, presents a possibility for an automatic assembly of the previously assembled units entering into the machine. One advantage of this method is that the arm shafts which pass through both the top and the bottom arm of the body do not have to be threaded through their bearings, but are placed sideways into their bearing seats and are fixed by bearing holders. Moreover, the majority of settings and adjustments can be carried out during the assembling from the open side of the body. The stitch-forming elements, that is to say, the needle and shuttle in a sewing machine, must have a well adjusted position in relation to one another in order to achieve a perfect execution of the stitch formation. The same applies also to the presser foot and feeder. An improperly set presser foot gives rise to irregular feeding and consequently an uneven seam. A concentration of the elements to a unit provides a greater opportunity for introducing adjustment and setting elements into the mechanisms, than when each element is fixed separately in the body of the sewing machine. Assembled mechanisms also represent an advantage from a service point of view, since a fault located in such a unit can easily be remedied by substituting the unit in question.